1. Field of the Present Invention
The present invention generally relates to the field of computer systems and more particularly to hardware and methods designed to secure computer system expansion cards in their respective connector sockets.
2. History of Related Art
Microprocessor based computer systems typically require or include facilities for connecting one or more expansion cards to the system. Expansion cards extend the capabilities of computer systems by providing dedicated hardware to achieve a variety of tasks. Graphics adapters, high speed network controllers, hard disk controllers, sound cards, and modem cards are among some of the more common types of expansion cards although those knowledgeable in the field of computer systems will recognize a wide variety of other types of expansion cards.
Typically, expansion cards are interfaced to the microprocessor (or microprocessors in a multi-processor system) by physically inserting the expansion card into an expansion card connector. In many cases, the expansion card includes facilities for making an external connection to the expansion card. A network adapter card, as an example, typically includes a socket for connecting an external cable to the adapter card. The expansion card must be maintained in a precise position such that the socket is accessible. Moreover, because external connections to expansion cards are achieved by incorporating expansion slots in the chassis of a computer system, it is important to maintain the portion of the expansion card that includes the socket or other external connector in close proximity to the chassis to minimize the gap between the expansion card and the chassis. In addition, it is important to maintain the positioning of expansion cards within their respective expansion card connector during system operation to insure reliable operation. Those familiar with expansion cards and expansion cards connectors will appreciate the ease with which a slight displacement or movement of the expansion card can result in a faulty connection. Thus, maintaining precise positioning of expansion cards is a an important issue in the design and manufacturing of computer systems. Historically, the secure positioning of expansion cards was maintained by screwing each expansion card into place with one or more securing screws. Unfortunately, the use of separate screws to secure each expansion board undesirably increases the amount of time and effort required to install, remove, replace, and otherwise service the expansion cards in a system.
A significant amount of effort has been devoted to simplifying the means by which the positioning of expansion cards is maintained. See, for example, Feightner (U.S. Pat. No. 5,694, 291) incorporating an intricately fabricated bracket apparatus to secure add-on cards in "Baby-AT" type computers; Carney (U.S. Pat. No. 5,706,173) disclosing a support and protective plate mechanism for engaging PCI cards; Carney (U.S. Pat. No. 5,673,175) teaching a complex, hinged, "double door" retainer for use with PCI cards; Lee (U.S. Pat. No. 5,575,618) reciting a cover member for securing expansion cards; Carney (U.S. Pat. No. 5,640,309) disclosing a clip mechanism for retaining PCI cards; and Holt (U.S. Pat. No. 5,601,349) disclosing a "captive latch" device for use with an expansion card cage. Unfortunately, these inventions typically require highly intricate clips, hinges, or bracket structures that introduce an undesirably expensive piece of hardware to the system component list. In addition, these inventions are typically effective at limiting expansion card movement in only one or two orthogonal directions. It would be highly desirable to introduce an easily manufactured and inexpensive expansion card retention mechanism that overcomes the limitations of the prior art.